a) Field of the Invention
The invention is directed to a tension shackle or clamping lock for antiskid chains with a housing having a deflecting element for a tension chain which runs over it, with a pawl which is swivelable between an open position and a locking position and which is pretensioned in a springing manner in its locking position against the deflecting element and has a projecting nose with which it locks the tension chain so as to prevent it from running through in the tensioning direction, and with a slot that is arranged on the side of the housing and extends over the entire height of the housing, through which slot the tension chain is introduced laterally into the housing from the outside and can be fitted on the deflecting element.
b) Description of the Related Art
In a known clamping lock of this type (DE 39 30 613 C2), the pawl is formed as a one-armed lever which projects out of the housing at the top and is provided in the region of its free end with a cross-piece so as to form a Tee, wherein the portion of the cross-piece projecting on one side of the lever serves as a nose of the pawl and the portion projecting on the other side serves for actuation by the user. For this purpose, the pawl presses with its nose against the tension chain from the outer side of the housing and on the outside of the housing and presses the tension chain against the outer surface of the deflecting element. When the nose, which is shaped like a wide leg projecting approximately vertically from the pawl, makes contact from above on a chain link of the tension chain, which chain link lies flat, and the tension chain is pulled opposite to the tensioning direction, locking is brought about because the next chain link following the chain link that is located under the nose stops against the front edge of the locking leg with its protruding web and cannot travel further. Because of the very small contact surfaces, very high area pressures occur, wherein there is a risk that the front edge of the locking leg responsible for the locking effect will be damaged if the tension chain is subjected to sudden pulling. This can lead to an impairment of overall operating ability. Also, the known clamping lock can be opened manually after a locking process only after the tension chain has first been pulled somewhat in the tensioning direction, because the locking leg (nose) of the pawl initially still stops against the shoulder of the previously locked chain link when opening, which requires an increased expenditure of force. When the tension chain is pulled in the tensioning direction, the utilized geometry cancels the locking by the nose of the pawl, but a relatively powerful pulling is also required for this purpose, since the leading or starting angle of the tension chain running out of the housing of the clamping lock relative to the underside of the locking leg is relatively large and the opening force is accordingly high. On the whole, this known clamping lock runs relatively stiffly due to its design, which also impairs its operating ability.